Azo dyestuff



Patented Apr. 18, 1944 UNITED STATES AZO DYESTUFF Swanie S. Rossander, Chiles E. Sparlraand -Carl;,; W. Maynard, Jig; Wilmington, l) el., -.-as signors,, to E. I. du Pont de Nemours & Company, Wile T mington, Del., a corporation of Del w re No Drawing. Application May'23,' 194l, Serial No..394,853-':..1.

The dyeing of textiles is frequently carried out 7 v 20% strength on an amine basis-with picollnic by impregnating the textile throughout with'the I acid and i'nactive diluents'such as sodiumsulfate coupling component of an azo dyestulf and overin such a=manner that the finished drysa-ltprepprinting with a paste containing a diazo salt.. aration contained l%'plcolinic'acid.-Aprinting By reaction of the diazo salt with the coupling paste of the following-compositlon was prepared: component a colored pattern is produced on the textile. The diazo salts incorporated in 'the "3 m: printing paste are of various typesysuc'h as diaj .-""-""TT i zonium halides, reaction products of "the azo; v component with zinc chloride 'orf-othermetallic l0 h h' g"'f'*"'* 66 halides, and-diazo salts which 'have b'een-preclpitated with aryl sulfonic acids. When incorpoi: r v.

rated in the printing paste, certain diazo salts des printin 'pa te was p intedfrom an teriorate rapidly, their deterioration being pare gra ed roller on omfibre. previously-treatticularly marked by loss in strength of colors 3'allilicle--..of.. "2,3hyd1' XY- flp th 0 made therefrom. Even so short a period of acid, a strong scarlet color resulted. When the standing as one day has frequently produced so same printing paste was used at successive time great a change that the paste was no longer usen ls r rin ing in t e s me manner, the fill for its intended purposes. persistence in strength of the resulting colors was The object of the invention, which has been far 1 5 to the Persistence stlfength of accomplished by the invention set forth in this those colors obtained from a Pa el Ser es 015 patent, was to produce printing pastes which do p inti s in which the Pa e used was made from not deteriorate so swiftly and keep their strength a i r diazo s p p i n c nt inin no longer. The printing pastes of our invention conp linic cid. The initial strengths of the colors tain, in addition to the diazo salt and the pasteo ed o e f e o p es ere the forming ingredients, a heterocyclic organic acid, same, but the Paste made from the unstablllzed or a metallic salt thereof, such as an alkali metal ia o salt lost stren th rapidly with p ysalt thereof. Other objects of the invention and ms t ni g and foaming, while the pas e ad their method of accomplishment will be in part from the stabilized diazo salt maintained its obvious and in part set forth hereinafter. strength and original physical appearance for The heterocyclic organic acids and their solu much longe pe ds o t e.

ble metallic salts which form a constituent of our new printing paste may be mixed with any ingredient of the paste prior to incorporation, or Experiment I was repeated, using fllTOiC i may be mixed with the fini hed paste If they in place of picolinic acid. Similar marked inare mixed with the diazo component, they can creases in the stability of the diazo salt printing Example ll be incorporated therewith prior to or after diazpaste as Compared with pastes n a i 0 Staotization. bilizer were noted.

ligxemplary of the heterocyclic organic acids Example III which are useful in this invention are furyl-acryl- I ic acid, S-bromo-furoic acid, thlonaphthene-2,3 A F Q paste was prepared by the dicarhoxylic acid, l-carboxy-acridone, carbazolefollowmg dlazotlzanon formula: 3-sulfonic acid, and quinolinic acid. It has also Parts been determined that the anhydrides of certain m Qhloro amlme hydrochlonde'ipicolmic of'these acids, suchas the anhydrides of thioand (111) naphthene-2,3-dicarhoxylic acid and of quino linic acid, can be effectively used as stabilizers. Hydrochlon? acld (315%) The invention is useful when applied to diazo 'f f F printing past-es containing diazo salt made from sodium mtnte (20%) any diazotized primary arylamine, examples of statch gumtragacanth thlckener which are diazo salts of the benzene, naphthasodmm acetate (50%) lene, anthracene, stilbene, and diphenyl series. The following examples illustrate the inven- 100-0 tion. In these examples parts are by weight and The paste was printed as in Example I, and was Proportions are illustrative of good Practice and found to be much more stable over a period of not limitations:

several days than was a similarly prepared printing paste in which the picolinlc acid ingredient The complex diazo salt from diazotized 2,5-di w mi e chloro-aniline and zinc chloride was isolated in Similar experiments with the stable complex the usual manner, dried, and diluted to about diazo salt from dlazotlzedmeta-chloro-anfllne Example I diazotization of the correspondin I which the diazo salts containing the stabilizing acids were used. The similar use of a disco salt prepared from diazotized meta-cbloro-aniline and naphthalene-1,5-disulfonic acid also gave attractive results. Additional experiments carried out in a similar manner on the diazo salts prepared from the following bases also gave increases in the relative stability of the resultant printing pastes: 4-nitro-2-amino-anisole, S-nitrc-i-amino-anisole, dianisidine, 3-nitro-4-amino-toluene, 5-nitro-2-amino-toluene., d-chloro-z-amino-anisole; and 5-chloro-2-amino-tolliene.

-The stabilization may be brought about by the use of various amounts of the stabilizing acid in the finished dry diazo salt We .prefer to use amounts of the stabilizer between five and fifteen percent of the finished dry diazo salt. The same result may be obtained by adding the stabilizing acid and the diam salt separately to the printing paste formula. or by incorporating the stabilizing agent at any stage after the first isolation in thepreparation of the disco salt, or by adding the stabilizing agent to a printing paste prepared by g base. It is not necessary to use the free organic acids, since the water soluble metallic ,salts such as the alkali metal salts of the acids are usually equally elective in their stabilizing action, and often present more attractive solubility characteristics. The anhydrides of the acids are frequently useful for the purposes of this invention.

The manner of drying the diazo salt, and the diluents .used in the finishing of the diam salt, haveno effect on the new printing pastes, provided, of course, that the diazo salt so prepared is otherwise satisfactory for printing purposes. Many diazo salts in common use do not keep'their strength in printing pastes for more than a few hours, while the same diazo salts, in many cases,

maintain their printing paste strength for several days when included in the pastes of our invention. The invention is of particular value where large amounts of printin mates are made up at one time, and used over a comparatively long period.

As manyapparently widely different embodiments of this invention may be made without tieparting from the spirit and scope thereof, it is to be understood that .we do not limit ourselves to the specific embodiments thereof except as defined in the appended claim.

We claim:

i A printing paste comprising an acid-reactin aryl diazo salt and picolinic acid.

- SWANIE S. ROSSANDER.

CHILE-S SPARKS. CARL W. MAYNARD, Jn. 

